The purpose of this study is to examine whether prolonged reduction of elevated plasma insulin concentrations in persons with NIDDM and in persons who are obese and insulin resistant are associated with increased insulin sensitivity and enhanced glucose uptake in muscle. Longitudinal and cross-sectional studies have provided evidence that hyperinsulinemia antedates the development of NIDDM and is thought to be a compensatory mechanism for overcoming the defect in insulin action. In this study, the investigators will use a continuous subcutaneous somatostatin infusion to lower the chronically elevated plasma insulin levels of healthy subjects with resistance to insulin and NIDDM patients, and to examine whether insulin sensitivity is improved.